Shadow Assassain
by ShadowCatcher
Summary: When a mysterious assassain joins the team, the Doctor knows there's something she's not telling them. And when unusual abilities come to light, the mystery deepens... Who is the Shadow? And what does it want with an assassain?
1. Prologue

**A/N: First fanfic! Please review. Flames welcomed.**

Prologue

The planet exploded in a fireball. All life gone.

Rocks floated out into space. They swirled. Flames leaped from some of them, causing beautiful yet deadly patterns. The stars dimmed in their light. Nothing left but rocks and flames.

A female leaned out of her ship. Her black hair gently billowed in her face. Sharp eyes took in the destruction. _So this is the price of war._

Tears leaked out of her eyelids. She closed them tightly, before looking over the destruction again. And she cried not only for the once beautiful planet, but for the place she had taken in this. Of the innocent people killed by her own hands. Of children, once laughing, now ashes on the wind. She took a deep breath. _What's done is done_. Why did it sound like she was convincing herself?

She glanced back to the complicated interior of her ship. Oh, she could fix this. But then her people would have died at the hands of the enemy. Death by flame.

Never again. She would live her life as someone else. She didn't deserve to be herself. The old her was gone. She would live her life working, eating, and sleeping. And remembering.

It was just her now. Her and the Doctor.


	2. Chapter : ISA

**A/N: Thanks for the review! Pls enjoy this chapter! And if I get some facts wrong in this story, don't hate me. I'm on season three. This will take place after The Satan's Pit and continue AU from there. Allons- y!**

 **Disclaimer: I do not own anything familiar.**

Rose POV

Rose grinned at the Doctor from across the TARDIS' console. "Where to now, captain?" _I was so afraid I'd lost you…_

He smiled back, crazy black hair whipping in the air as he spun to the console. He flipped a few levers. "Oh, how about…" He trailed off and hit a button. With a shake, the TARDIS started the journey. Rose's grin grew wider. The TARDIS began to jostle and they both held on to the console. With a jarring thump, it landed. Rose gave the Doctor a thumb- up and headed for the door.

Outside, it was a beautiful day. The sky was a deep sapphire blue with wispy clouds floating across its surface. The sun shone brightly from nearly directly overhead. Grass poked up from between slabs of pavement.

They were in an alley. Building hemmed in the TARDIS and the sapphire sky. Birds tweeted from above. Other than that, it was silent. Rose spun around to see the Doctor leaning against the side of the TARDIS. "Where are we?" she questioned. Her brown eyes examined the alley.

"New York City, January 22, 2016." He looked around. "A quiet place. No crimes or emergencies. New year revolutions are probably being broken as we speak."

 _Right, and I'm Harriet Jones_.

A man staggered down the alley. Against her better thoughts, she took a step towards him. "Excuse me, sir, where are we and what year is it?" He gave her a look that clearly said he was drunk. He smiled.

"You mus' be as drunk as meee. It's 2015, and we're iz Mobile, Alabama." He continued down and disappeared around a corner.

` The Doctor raised his brows. Rose smirked. "I don't care if he was a serial killer because I had to prove you wrong. And guess what? I did! We're in Alabama, not New York." He shrugged. He walked up to her and offered his hand.

 _TAP TAP_

The Doctor realized what it was first. Spinning, he grabbed her left arm as she cried up in pain and curled her right against her chest. The Doctor sprinted inside the ship. Two more bullets hit the TARDIS' hard outer shell. He released her and grabbed the console. He began to rapidly hit buttons. "C'mon!" he yelled. The TARDIS shook and landed in a new place with a bump.

The Doctor walked over to Rose and gently took her right arm. A rip stretched about four inches down her brown shirt. Rose looked at him. "Can you fix it?" The Doctor snorted.

"You insult me and the TARDIS. Of course I can. I am the Doctor after all." He led her down the halls. Fifteen minutes later, she was healed and wore a new pink and brown blouse.

The Doctor slowly opened the doors. Sunshine shone through. The sound of bullets was absent. He carefully stepped outside. Nothing. Suddenly grinning, he extended his hand to Rose. Rose smiled back and accepted it. He led her outside. "Welcome to Home Sweet Home Alabama."

Rose's brows rose. "You been here before?"

The Doctor peered around. "Yup. A little squat with some Feders. Quite nasty creatures, those. Kinda like Slitheen. A bit taller, though." His face scrunched up. "More hairy, too. They emit sonic pulses. Fixed them. Turns out, they detest water. Turns them into acidy slimy puddles." Rose snorted.

"I don't know if I believe that they are destroyed by water. What are they, products of the wicked witch of the west?" The Doctor's face resumed his injured look. The now familiar _tap_ on concrete halted his retort.

He tried to turn and push Rose back to the TARDIS, but three bullets smacked the pavement between them and the ship. They turned to hide underneath a nearby oak tree, the only cover in the pasture they had landed in, but another two bullets blocked that. The Doctor took a deep breath and pulled Rose behind him. But because he had no idea where the shooter was, it was helpless.

"Who are you?" the Doctor called out. An amused chuckle floated across the air. His head whipped around. But the echo stopped his pinpointing. But there were only three places the shooter could be; all were hills- to their left, right, and leftish frontish.

"I'm an assassin. Boo!" the slightly masculine voice snickered.

Rose straightened and looked at the hills. " _Where_ are you?" A shadow shifted across the hill to the right.

"Right here. And catch!" Two objects sailed through the air toward them. The Doctor grabbed his while Rose fumbled before securing it. The Doctor flipped it around. Blue beads decorated wire string. The largest one was blinking white rapidly. He realized what it was.

"Rose! Drop it! It's a-" The pasture swirled around them. Their eyes slammed shut. They landed with a jar onto a hard tile floor.

Rose groaned and opened her eyes. _Teleport._ "Thanks for the warning, Doctor," she muttered. Her stomach rolled. She stumbled to her feet. The room hazed before becoming clear. She stood in a large room. Underground, if the lack of windows said anything. A single light illuminated the middle of the room, which was where they stood. Or in the Doctor's case, lay. _Speaking of the Doctor_ …

"Hey, Doctor?" She leaned down over him. His head was laying across the floor and a bruise appeared to be forming. Unconscious, probably. _Time Lords don't lose consciousness!_ She snickered in her mind.

"Why, hello." Rose turned. A man stood, half visible, in the shadows. He was tall and slim. Beady brown eyes examined them.

"Why are we here?" Rose demanded. He shrugged.

"I'm not the one who brought you here." He nodded his head to the opposite side of them. Rose's head whipped that way to nothing. She looked back at the man, but he was gone. "Blimey." A laugh. She quickly turned to the voice. It was the same voice from before.

"I see we got a Londoner. Quite a way from home. Welcome to the U.S. The land of the free and the home of the brave. And terrorist groups." Rose stiffened.

"You're a _terrorist group_!"

"No, I just say that 'cause it sounds cool," the voice deadpanned. A beat of silence. "Of course I'm part of a terrorist group! Londoners are just getting stupider and stupider as the years go by." Rose frowned. "Oh, and the group's ISA. I- intelligence. S- Secrecy. A- Assassination."

"Thanks." A snort. "But, now that we've established that, can I see you?"

Silence. Finally, "Do you really want to?" The voice had changed. It sounded younger, neutral, more shaky.

"Of course." _I've seen Slitheen, Daleks, Cybermen, empty children, and possessed men. What could be worse?_

A figure stepped into the light. It was small and wiry. Red brown hair was pulled up in a ponytail and blue green eyes regarded her. 'What could be worse?'

A lot, apparently.


	3. Chapter 3: Addi

**Here we go again! I'm proud of myself. Enjoy and don't forget to reveiw! Flames are welcomed.**

 **Nothing familiar is mine.**

Rose's POV

It was a girl.

A bloody school girl. No older than fourteen. She was around 5'5 and wiry. Her eyes were hard and her posture tense. She wore a deep black t- shirt with a light grey sweat over it. Her jeans were dark navy with rips down the thighs. She wore blue and grey sneakers. A necklace of a black dolphin hung tightly around her neck. But what was so disturbing was the gun. A sniper rifle, slung over her left shoulder by a black strip. Silenced, if the lack of sound before said anything.

"Well, here I am." She spun around, hair flying out behind her. She stopped and threw a cheeky wave. A fake smile turned up her lips. She did a mock bow. "Addi, at your service. First class assassin of ISA. Seventeen successful missions." _What?!_

Rose blanched at the missions. "You've killed seventeen people?"

"Yup. Let's see… a navy officer, a millionaire, an ice cream vendor secret agent person, some Italian man…" she began to tick off her targets.

"Stop!" Rose yelled. "Just stop! I don't want to hear about your kills!" The girl stopped and shrugged.

"Suit yourself. Oh, how's the Doctor man doin'?" She slid over to him like a ghost. She opened his eyelids. Felt for a pulse. Knocked on his forehead. Felt for a temperature. Asked about any medications ("he's allergic to them," Rose had huffed), and finally she had just kicked his side.

"That's enough!" Rose exclaimed, exasperated. "He's just knocked out. He's got a bruise on the side of his face." The girl checked that.

She gave Rose an annoyed look. "You _could_ have said that at the beginning, you know."

A man stormed over to them from a shadow. "Addi! You were supposed to kill them, not have a social conference with them!" He glared at her. The girl, Addi, gave him an innocent look before standing up and brushing dirt off her jeans.

"I was just making sure the man was alright. And for the reason they're breathing? I honestly don't know." She frowned over at Rose. "Why did I let you live, again?"

"Ah…" Rose racked her brain for something of use to these people. Well, they were terrorists. So what would be an enemy of terrorists? Law enforcement. What types of enforcement did America have? Man, she wished she had paid more attention during class. There was only one she knew of. But did they know about them? "We were having a, um, problem with Torchwood."

She looked between them. Then it hit her. _CIA! FBI! God, I'm stupid._ Their faces were unreadable. Addi and the man had locked eyes.

"Good, then maybe you can help us," the man finally stated. "Or at least as soon as the Doctor wakes up." He trapped the girl in his gaze. "You know what to do. Maybe they won't destroy us for not completing the mission if their up in smoke." He chuckled as he left.

Rose shifted from one foot to another. "What mission, exactly?" Addi turned to look at her. She was quiet, choosing her words.

"Torchwood were the ones that gave us the order to kill you. They offered us a large amount of money. One hundred thousand dollars." She shook her head.

"Excuse my lack of knowledge, but what is that amount in pounds? And there's a Torchwood in America?" The girl froze as she thought. Rose glanced back at the Doctor. He was still soundly unconscious.

The girl looked again at Rose. "Roughly around seventy thousand pounds. A small fortune for two people. Should have been easy. What made me teleport you instead of kill you, I wonder?"

"It was me." They both spun around at the Doctor's voice. He held up a small silver key. "TARDIS key. Can create small telepathic links. I pretty much just whispered in your mind to not kill us. A bit like magic." He considered for a moment. "But magic isn't real. So not really. But pretend it is."

Rose launched himself into him. "You crazy alien! Knocking yourself out like that!"

"He was only unconscious for a few minutes. By the time I revealed myself, he was awake. I could tell by the way his eyes and hands were twitching. Nice show, Doctor." Addi rolled her eyes.

The Doctor pried Roe off before frowning at the girl. "I'm sorry, what was your name again?"

"Addi." She reminded him. "First class assassin of ISA, Seventeen successful missions. Two half- completed missions."

"Right. Well, Addi, what's the plan? And the backstory, that would be nice."

"Which backstory? Mine or ISA's problem with Torchwood?" she questioned.

"How about both. Though I was thinking your back story." She sighed. She beckoned them. The Doctor leaped to his feet and followed her, Rose trailing behind. She entered a door where it was nearly completely dark. Rose grabbed the Time Lord's hand as they entered into complete darkness. There was a scratching sound before light shone on at the end of the hall.

"Sorry 'bout that," Addi stated from ahead of them. "They seem to move the light switch to a new place every day. Stupid electricians." She led them into a smaller room, still muttering, and turned on the lights. The room was about a quarter of the other room's size. Half of the room was taken up by desk and computers, the other chairs and tables. "Group's at home." Addi walked over to a computer and flicked it on. "C'mon."

The Doctor slid out his glasses and fixed them on. He stood behind her. Rose peered over his shoulder. The screen turned bright green before settling into a light black. Addi's hands flew across the keys as she entered a ten- digit passcode.

"And don't even think about trying that. The passcode changes every time it's used." She shot a glare at the Doctor. He raised his hands harmlessly before his brow furrowed.

"Then how exactly do you know what it is?" he asked. She glanced at him before tapping a watch on her right hand that Rose hadn't noticed before. "It's a Applewatch version seven. A very good one for storage. I put in my personal passcode and access the password."

Rose thought back to their adventures. "I don't remember there being an Applewatch seven…"

A shrug. "Then look again." She began typing and windows flew by on the screen. Silence settled on the group. Finally, the Doctor broke it.

"So how exactly do you know about us being the Doctor and Rose. And you seem comfortable with the time traveling stuff we've been talking about. Care to explain?" he questioned. Addi didn't respond besides glancing over her shoulder at him.

"ISA stands for three things. The I stands for intelligence. Intelligence means information. Information means files. Files means hacking. Hacking means Torchwood. Torchwood means information on you two," she explained slowly.

"You didn't have to say it like we were toddlers," Rose grumbled. Nobody responded. She looked over the Doctor's shoulder again to see Addi had pulled a page up and was letting them read it.

 _11/24/15_

 _01:31 PM_

 _Torchwood once again contacted us with more demands: Assassinate Emily Smith, John Keels, and Telia Jermones. They also instructed us to send our best assassin. Our punishment for not succeeding within the time limit of forty- eight hours would be losing another ten of our members._

 _11/25/15_

 _05:02 PM_

 _We failed one assassination. We lost four members. We are slowly losing traction. We received another set of instructions: Assassinate Cory Williams and Kiro Klye. We have thrity- six hourse. Punishment is seven members…_

"So Torchwood is destroying you," the Doctor summarized. He jerked Rose out of reading.

"Exactly," Addi responded. "ISA was once one of the largest terrorist group with nearly a million members. Now we are down to a little over twenty thousand. We're ready to take our revenge. There's only one Torchwood here in the U.S.- this one here in Mobile. That's why we're here. The others are in London, Paris, Quebec, and other large cities." She turned in her chair to look at them. "So, will you help us?"

"I expect it's either help or die. Because first of all you're a terrorist group, we're trapped, you are touching your gun-" the Doctor began.

"Yes," Rose interrupted, "we'll help."


End file.
